Enter the world's largest indoor miniature theme park Small Worlds Tokyo, which was newly opened in 2020 at Ariake, Tokyo! Enter the world's largest indoor miniature theme park, Small Worlds Tokyo! Having just opened its doors in June of 2020, this colossal indoor wonderland offers a one-of-a-kind experience for visitors of all ages. Spanning over 8,000 square meters (approximately 86,000 square feet), Small Worlds Tokyo features intricate and realistic miniature dioramas showcasing various scenes and locations from around the world.